Stable compositions useful in the compounding of photographic developers



Patented Dec. 19, loss STABLE CONEOSITIONS USEFUL 1N TM COMPOUNDING OF PHOTOGRAEEC DE- VELOPERS Lowell E. Muehler, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y a corporation of New Jersey No Drawing. Application March 29, 1939, Serial No. 264,847

8 Claims.

developer with two objects in view: (a) To harden the gelatin, and (b) to generate alkali as a result of interaction with sodium sulfite according to the following equation:

m CI-IzO-l-NazSO:+mO=NaH+NaHSOaCHOH It is possible, therefore, to prepare package developers having a high degree of activity without the use of caustic soda. "Developing solutions containing formaldehyde and sodium sulflte possess the disadvantage that they are easily oxidized because some of the sulfite tends to form formaldehyde-bisulfite. Furthermore, such developers have the additional drawback that when they are allowed to stand in closed containers polymerization of the formaldehyde occurs and the polymer, either does not react at all with sodium sulfite, or it reacts so slowly that the normal course of the reaction to produce alkali is not followed.

In order to avoid the above reactions, namely, oxidation and polymerization, it has been proposed to separate the formaldehyde from the developing agent-sulfite solution by making up two separate solutions, one containing the formaldehyde and the other containing the developing agent per se, and the second solution added to the developer as desired. When a formalin solution, that is, a solution in-which formaldea hyde gas is dissolved in water, is employed, this is ordinarily sumciently stable and no polymerization and no loss of formaldehyde due to polymerization occur. When, however, a solid polymer of formaldehyde such as paraform- 63 aldehyde or trioxymethylene, as it is sometimes called, is employed in place of formalin, it is diihcult to get the solid into solution. Consequently, it is necessary to add an alkali, for example, sodium sulflte, in order to cause the paraformaldehyde to go into solution. However, as indicated above, available formaldehyde tends to undergo a loss by formation of an insoluble polymer, such reactions taking place readily in the presence of alkali.

a This invention has as an object to obviate the As is known, formaldehyde may be added to a above-'mentioned dificulties involved in the use of paraformaldehyde as a source of alkali in a developing bath. A further object is to provide a means whereby a solid polymer of formaldehyde, such as paraformaldehyde, may be employed in aqueous solution in connection with sodium sulflte without the resulting formaldehyde undergoing polymerization and thus decreasing I the source of formaldehyde in the solution. Another and specific object is to provide in crystalline or powder form a composition which, when dissolved in water, will provide an appropriate source of formaldehyde for addition to a solution containing a photographic developing agent and sodium sulflte. A further specific object is to provide a two-package photographic developer which may be sold in dry form and adapted for the making up of two stock solutions and the, preparation of the developing bath itself. Other objects will appear hereinafter.

These objects are accomplished by the following invention, which, in its broader aspects, comprises the discovery that a composition in dry powder form possessing the ability to be dissolved in water to produce a stable formaldehyde stock solution may be compounded by mixing in appropriate proportions paraformaldehyde sodium, suliite and a solid acid such as boric, glutamic, phenylacetic, citric, tartaric, malic acids or a buffering salt such as the alkali metabisulfites, the alkali bisulfites, the alkali borates, metaborates, monoand di-sodium phosphate, and the like. Ammonium salts such as ammonium chloride are also suitable neutralizing saltsin the presence of the formaldehyde. I have found that such dry powdered compositions are stable, readily handled, and when simply dissolved in water in appropriate proportions, provide a highly satisfactory and stable formaldehyde stock solution which is not subject to loss of formaldehyde by polymerization.

Also included within the broad scope of my invention is the provision of a two-package developer in dry form, one package containing the ingredients essential for the provision of the above-mentioned stable formaldehyde stock solution and the other containing the ingredients necessary for the provision of the developer stock solution itself.

In the following examples and description I have set forth several of the preferred embodiments of my invention, but it is to be understood that they are included merely for purposes of 11- lustration and not as a limitation thereof.

As indicated above, the paraformaldehyde of M commerce is insoluble in water, but readily soluble in solutions of alkalis and solutions of sodium sulfite. The main difllculty, however. has been that the excess alkali required to get the paraformaldehyde into solution results in the above-mentioned polymerization. The present; invention is based upon the concept of neutralizing the alkali by a suitable acid or bufler salt after the paraformaldehyde' has been placed in solution. Thus, the excess alkali may be removed from the solution by a straight neutralization reaction' or the solution may be buffered by means of dior tri-basic acids or suitable bufiering salts such as those indicated above. The solution then consists essentially of formaldehyde and water at a definite pH depending upon the composition of the bath. In general, I prefer to keep the pH of the solution below ll and this may be accomplished by employing the acid or buffer salt in an amount sumcient to maintain the pH at the desired value. It is also desirable that the total concentration of alkali in the solution be as low as possible. While no definite low limit of pH of the solution can be set, this may be as low as two or three, the preferred range being from 3 to 11.

The following. examplesillustrate dry compositions suitable for the production of the form aldehyde stock solution and/or the developer per se. Inasmuch as these compositions are provided as one of the components of a two-package combination for making up a developing bath, the

examples also include references to a typical composition which may be employed as the source of the developing agent. These two compositions may be referred to as the A composition and the B composition, the A composition being the source of the developing agent per se and the B composition being the source of the formaldehyde.

It will of course be understood that the reference to the amounts of water to be added to any of the following compositions is included simply to indicate the appropriate manner of making up the solutions desired in actual practice. The present invention, however, relates only to the solid compositions comprising various B mixtures.

Example 1 B. Paraformaldehyde .(trioxymethylene) grams 30 Sodium sulfite (desiccated) gram 1 Potassium metabisulflte (cryst.)

grams 10.5

. Water (about 100 F.) to make liter 1 A. Water (about 125 F.) (52 C.) llters 2.0 Sodium sulfite, desiccated grams 120.0 Boric acid do.. 30.0 Hydroquinone do 90.0 Potassium bromide do 6.3 Cold water to make liters 3.0

Example 2 B. Paraformaldehyde ..grams 30 Sodium sulflte (disc.) gram 1 Sodium bisulfite (cryst.) grams 9.4 Water (about 100 F.) to make.. liter 1 A. Same composition as A COW tof Example Example 3 B. Paraformaldehyde grams 30 Sodium carbonate (desiccated) do.. 10 Sodium bicarbonate do 40 Water (about 100 F.) to make liter 1 A. Water (about 125 F.) (52 C.) liters 2.0 Sodium sulfite, desiccated grams 120.0

Hydroquinone do 90.0 Potassium bromide do 6.3 Cold water to make liters 3.0

Example 4 B. Paraformaldehyde grams 30 Sodium sulflte (desiccated)' do 20 Resorcinol do 32 Water (about 100 F.) to make liter 1 A. Sodium sulfite (desiccated) grams 100 Hydroquinone .do Potassium bromide do 6.3 Water (about 125 F.) to make liters 3 Example 5 B. Paraiormaldehyde grams 30 Sodium metaborate (Na2BzO4.8H2O) I grams-.. 15 Water (about F.) to make liter 1 A. Sodium sulflte (clesiccated) grams Hydroquinone do 90 Borlc acid (crysts) do 30 Potassium bromide do 6.3 Water (about F.) to make liters 3 Example 6 B. Paraformaldehyde grams 42 Sodium sulfite (desiccated) do 52 Glycine (crystals) (aminoacetic acid) grams" 30 Water (about 100 F.) to make liter 1 A. Sodium sulfite (desiccated) grams 78 Hydroquinone do 90 Potassium bromide do 6.3 Water (about 125 F.) to makeulitersu 3 v Example 7 B. Parafonmaldehyde grams 30 Sodium sulfite (desiccated) do 20 Borlc acid (crystals) do 7.5 Water (about 100 F.) to make liter 1 A. Water (about 125 F.) (52 C.) liters 2.0 Sodium sulfite, desiccated grams 120.0 Boric acid do 22.5 Hydroquinone do 90.0 Potassium bromide do 6.3 Cold water to make ..liters 3.0

Example 8 B. Para-formaldehyde grams 30 Sodium sulfite (desc) 'do 24 Malic acid (crystals) do 12.! Water (about 100 F.) to make liter.. l

A. Water liters 2.0 Sodium sulflte', desiccated grams 120.0 Boric acid do 30.0 Hydroquinone do 90.0 Potassium bromide do 6.3 Cold water to make liters 3.0

Example 9 B. Paraformaldehyde grams 30 Sodium sulflte (desc do 11.9 Sodiumhydrogen malate (cryst.) do 14.8 Water (about 100 F.) to make liter- 1 A. Water (about 125 F.) (52 C.) liters 2.0 Sodium sulfite. desiccated grams 120.0 Borlc acid do 30.0 Hydroquinone do 90.0 Potassium bromide do 6 3 Cold water to make liters Example 10 Sodium sulfite "grams-.. Paraformaldehyde do Ammonium chloride cryst do- Water to make "liter-..

. Sodium sulfite -1 grams Hydroquinone do Boric acid cryst do Potassium bromide do Water to make liters Example 11 Sodium sulfite grams-.. Paraformaldehyde do Tartaric acid (M -V2" crysts) do Water 100 F. to make liter Sodium sulfite grams Hydroquinone do Boric acid do Potassium bromide do Water to make liters Example 12 Sodium sulflte grams Paraformaldehyde do.. Dlsodium hydrogen phosphate Na2I-IPO4J2HzO do Water 100 F. to make liter Water (about 125 F.)' (52 C.) liters Sodium sulfite, desiccated grams- Boric acid do Hydroquinone do Potassium bromide do- Cold water to make liters Example 13 Sodium sulfite grams Paraformaldehyde do Sodium dihydrogen phosphate (large crystal aggregates V -ld") NaHsPOaHzO grams Water 100 F. to make llter Water (about 125 F.) (52 C.) liters.. Sodium sulfite, desiccated grams Boric acid. do Hydroquinone do Potassium bromide -do Cold water to make liters Example 14 Sodium sulfite "grams" Paraformaldehyde -do Phenyl acetic acid (large plate crystals) ,grams Water 100 F. to make liter Water (about 125 F.) (52 C.) liters Sodium sulfite, desiccated grams Boric acid do Hydroqninnne (in Potassium bromide do Cold water to make liters Example 15 Sodium sulflte grams Paraformaldehyde do d-Glutamic acid (fi -Y cryst. aggregates) grams Water 100 F. to make liter Water (about 125 F.) (52 0.) liters Sodium sulfite, desiccated grams Bgric acid fin Hydroquinone do Potassium bromide do 7 Cold water to make -liters Erample'lfi 11.9 B. Sodium sulfite grams 10.0" 35 Paraformaldehyde do 30.0 5 Arsenic trioxide do 9.3 1 Water 100 F. to make liter 1 120 A. Water (about 125 F.) (52 C.) liters 2.0 90 Sodium sulflte, desiccated grams 120.0 30 Boric acid do 30.0 6.3 Hydroquinone 1 do 90.0 3 Potassium bromide do 6.3 Cold water to make liters 3.0

119 In employing the above solutions, one part of solution B is added to three parts of solution A 79 to make up the developing bath.

1 In general, a solid acid salt or acid having a relatively large particle size should be employed 140 in compounding'the dry composition in accord- 90 once with the present invention, since the rate of 30 solution of the acid salt or acid should not be in excess of the rate of solution of the paraform- 3 aldehyde and sodium sulfiter If it is desired to use a solid acid in a relatively fine state of subdivision or small particle-size, agglomeration of the acid with suitable ln'ert binder may be desirable in order to reduce its rate of solution below 0 that of the paraformaldehyde.

As indicated above, the entire mixture of inh gredients of the dry composition can be added to 12Gb water and dissolved completely within a few minutes. Many variations of the formula are 960 possible within the scope of my invention. For example, alkali bi-sulfites may be substituted by the alkali metabisulfite and other acid salts or acids may be substituted for the metabisulfite. The alkali sulflte may likewise be replaced with n 9 an alkali carbonate or other soluble alkaline salt 30') if proper provision is made for neutralizing or decreasing the alkalinity of the solution by use of an acid or buffer salt as herein set forth. 13 0 Various fog-restraining or inhibiting substances may be added to either of'the dry compositions, such as phenosafranine, Pinakryptol 2.0 Green, arsenious oxide, or the alkali salts of 120.0 arsenious acid such as sodium arsenite, potassium 30.0 ferrocyanide or other alkali ferrocyanides and 90.0 others. 'In the case of phenosafranine, varying 6.3 amounts may be used, but a suitable restraining 3.0 vaction is obtained when about one part in 150,000 parts of the mixed developer is used. 119 When using arsenious oxide, sodium arsenite or 300 similar compounds, two grams per liter give representative and satisfactory results. 123 The present invention has many advantages, 1 the chief of which is the fact that it is possible to provide a two-package developer in dry form 2.0 in which the package containing the source of 1203 formaldehyde is provided with a means of stabilizing the formaldehyde when dissolved to make 909 up the B solution. By my invention one is thus 6.3 enabled to purchase the dry material in a form in which it does not deteriorate, either in the package or in the stock solution when made up.

It is to be understood that the solid compositions of my invention constitute an entirely distinot and separate entity from the aqueous solutions resulting from dissolving these materials in water. In other words, whereas the dry mix- 1 ture contains certain specific chemicals, many of 2.0 these more or less completely lose their identity 120.0 in solution. As is well known, photographic solutions are rather highly complex in their composi- 90.0 tion and the ingredients must be present in def- 6.3 inite and exact proportions in order to obtain the 3.0 desired result.

tal size that its rate of solution is less than the other constituents in order that the alkalinity of the solutiongbe maintained at a sumciently high value to dissolve the paraiormaldehyde.

What I claim is: 1. A composition in solid form adapted to dissolve in water for the purpose of providing in- Solution a suitable source of formaldehyde for addition to a solution containing a developing agent and sodium suliite to prepare a photographic developing bath, said composition comprising paraformaldehyde, an alkaline salt. and a solid agent adapted to act as aneutralizlng or buffering agent.

2. A composition in solid form adapted to diesolve in water for the purpose of providing in solution a suitable source of formaldehyde for addition to a solution containing a developing agent and sodium sulflte to prepare a photographic developing bath, said composition comprising paraiormaldehyde, sodium sulfite, and a solid agent adapted to act as a neutralizing or bufiering agent.

3. A composition in solid form adapted to dissolve in water for the purpose of providing in solution a suitable source of formaldehyde for addition to a solution containing a developing agent and sodium sulflte to prepare a developing bath, said composition comprising paraformaldehyde, an alkaline salt, and a solid agent adapted to dissolve more slowly than the'other constituents and act as a neutralizing or buffering agent.

4. A composition in solid form adapted to dissolve in water for the purpose of providing in solution a suitable source of formaldehyde tor addition to a solution containing a developing agent and sodium sulfite to prepare a developing bath, said composition comprising paraformaldehyde, sodium sulflte, and a solid agent adapted to dissolve more slowly than the other constltuents and act as a neutralizing or bufiering agent.

5. The product of claim 1 in which the agent is a solid acid.

6. The product oi claim 1 in which the solid agent is selected from the group consisting of boric, glutaniic, phenyl acetic, citric, tartaric, or malic acids.

7. The product of claim 1 in which the solid agent is a salt selected from the group consisting of the alkali metabisulfites, the alkali borates, alkali metaborates, and the monoand di-sodium phosphates.

8. The product of claim 1 in which the solid agent is an ammonium salt which, in the presence of excess formaldehyde, gives rise to acid.

LUWELL E. DEUEHLER. 

